Forex bucket shops that pretend to be brokers but really trade against you. Many times killing accounts with big bid/ask spreads.
Using attractive female photos to push some service off on traders.
Trading newsletter writers that don’t even trade. They issue a lot of buy signals then cherry pick the winners to tout to the public.
Penny stock pump and dumps. If you trade stocks with almost no liquidity and that are under a penny you are going to have a bad time. However there are some legitimate opportunities to invest in penny stocks such as learning strategies and opportunities through an educational portal–an example is Penny Stocks Lab.
Mutual fund managers that take big management fees and under perform their benchmarks.
Twitter traders that delete their losing trade tweets. Their egos may be a problem.
Ads selling the can’t lose ‘Holy Grail’ trading system.
Talking heads spewing out useless opinions on financial television.
Buy and hold equities being taught as the best investing system.
The efficient market theory and that it is impossible to beat the market over the long term.